Identification of a 3-(5-methyl-2-thiazolylamino)phthalide as a new minor groove agent.

A new 3-(5-methyl-2-thiazolylamino)phthalide molecule, 3-((5-methylthiazol-2-yl)amino)isobenzofuran-1(3H)-one, was synthesized and characterized experimentally by FT-IR, NMR, UV-Vis, and single-crystal X-ray analysis and theoretically by quantum chemical calculations. The single-crystal X-ray studies revealed that the compound crystallizes in the monoclinic space group P-21/c with unit-cell parameters a = 8.0550(6) Å, b = 6.1386(3) Å, c = 23.3228(18) Å, ß = 97.724(6)° and Z = 4. Optimized geometries and the vibrational frequencies were studied at the density functional theory (DFT) level by using the hybrid functional B3LYP with a 6-311 G (d,p) basis set. The title compound was evaluated for its anti-quorum sensing (anti-QS) activity on Chromobacterium violaceum 12472 and additionally for its antibacterial activity against Staphylococcus aureus 29213, Staphylococcus epidermidis 12228, Pseudomonas aeruginosa 27853, Escherichia coli 25922, and Proteus mirabilis 14153. The lowest MIC value was 0.24 µg/mL for S. aureus 29213 and the highest MIC value was 30.75 µg/mL for E. coli 25922. While anti-bacterial activity was observed in those other than the S. epidermidis and P. Mirabilis, anti-QS activity wasn't detected. Investigations on dsDNA binding affinity indicate that the title compound binds to dsDNA via the groove binding mode. Molecular docking calculations and molecular dynamics simulations results showed also that the title compound prefers binding to the minor groove of dsDNA and remains stable in the minor groove throughout the molecular dynamics simulation.Communicated by Ramaswamy H. Sarma.

Synthesis, crystal structure, spectroscopic features and Hirshfeld surfaces of 2-methyl-3-[(2-methyl-phen-yl)carbamo-yl]phenyl acetate.

The title compound, C17H17NO3, was synthesized, characterized by IR spectroscopy and its crystal structure was determined from single-crystal diffraction data. The asymmetric unit contains two mol-ecules, which adopt different conformations. In one mol-ecule, the acet-oxy and the terminal 2-methyl-phenyl groups are positioned on opposite sides of the plane formed by the central benzene ring, whereas in the other mol-ecule they lie on the same side of this plane. In the crystal, the mol-ecules are linked through strong N-H⋯O hydrogen bonds into chains along [010]. Hirshfeld surface analysis and fingerprint plots were used to investigate the inter-molecular inter-actions in the solid state.

Synthesis, structural and computational characterization of 2-amino-3,5-diiodobenzoic acid and 2-amino-3,5-dibromobenzoic acid.

The benzoic acid compounds 2-amino-3,5-dibromobenzoic acid (2A35Br) and 2-amino-3,5-diiodobenzoic (2A35I) acid have been synthesized and characterized by single-crystal X-ray diffraction, FT-IR spectroscopy, UV-Vis spectroscopy and computational methods. Molecular geometry, intra- and inter-molecular interactions have been investigated by using X-ray diffraction technique. Fundamental vibrational bands of the title compounds were founded by FT-IR and UV-Vis method was used to obtain electronic bands. Geometry optimizations and the calculation of IR frequencies were performed both Gaussian type orbitals at Gaussian 09W and Slater type orbitals at ADF2009.01 software. The calculations are compatible with the experiment results. In addition, geometrical parameters, energies, HOMO-LUMO gaps and electrophilicity indexes have been calculated for thirty possible positional isomers of 2A35Br and 2A35I. Calculations show that 2A35Br and 2A35I isomers have the lowest energy, the narrowest HOMO-LUMO gap and the highest electrophilicity index values. Molecular electrostatic potential maps, Fukui indices, natural bond orbital analysis, thermodynamic parameters and non-linear optical properties of the 2A35Br and 2A35I were also investigated by theoretical calculations.

Existence of a resonance hybrid structure as a result of proton tautomerism in (±)-(E)-4-bromo-2-[(2,3-dihydroxypropylimino) methyl]phenol racemate.

o-Hydroxy Schiff bases have two tautomers known as phenol-imine and keto-amine forms. In the present work, the tautomerism in (E)-4-Bromo-2-[(2,3-dihydroxypropylimino)methyl]phenol compound has been investigated by experimental (XRD, FT-IR and UV-vis) and computational (DFT and TD-DFT) methods. The X-ray diffraction (XRD) study reveals that the title compound favors a resonance hybrid structure of phenol-imine and keto-amine forms in the solid state rather than having these forms separately or jointly. Experimental UV-vis study of proton transfer process in solvent media (Benzene, DMSO and EtOH) shows the preference of phenol-imine form in benzene while both phenol-imine and keto-amine characteristics are present in EtOH and DMSO.

The prototropic tautomerism and substituent effect through strong electron-withdrawing group in (E)-5-(diethylamino)-2-[(3-nitrophenylimino)methyl]phenol.

The prototropic tautomerism in o-Hydroxy Schiff bases results in two forms called phenol-imine and keto-amine. The preference of a particular form by the compound changes in the solid and solvent media. The choice can also be regulated by a substituent with a different electron-donating or withdrawing group. In the present study, the above-mentioned factors are considered in the investigation of (E)-5-(diethylamino)-2-[(3-nitrophenylimino)methyl]phenol compound (an o-Hydroxy Schiff basis) by experimental (XRD, FT-IR and UV-vis) and computational (DFT and TD-DFT) methods. The results show that the title compound adopts only phenol-imine form in the solid and solvent media. This was attributed to the substituent effect through strong electron-withdrawing nitro group.

Survey of conformational isomerism in (E)-2-[(4-bromophenylimino)methyl]-5-(diethylamino)phenol compound from structural and thermochemical points of view.

In this study, (E)-2-[(4-bromophenylimino)methyl]-5-(diethylamino)phenol compound was investigated by mainly focusing on conformational isomerism. For this purpose, molecular structure and spectroscopic properties of the compound were experimentally characterized by X-ray diffraction, FT-IR and UV-Vis spectroscopic techniques, and computationally by DFT method. The X-ray diffraction analysis of the compound shows the formation of two conformers (anti and eclipsed) related to the ethyl groups of the compound. The two conformers are connected to each other by non-covalent C-H⋯Br and C-H⋯π interactions. The combination of these interactions is resulted in fused R(2)(2)(10) and R(2)(4)(20) synthons which are responsible for the tape structure of crystal packing arrangement. The X-ray diffraction and FT-IR analyses also reveal the existence of enol form in the solid state. From thermochemical point of view, the computational investigation of isomerism includes three studies: the calculation of (a) the rate constants for transmission from anti or eclipsed conformations to transition state by using Eyring equation, (b) the activation energy needed for isomerism by using Arrhenius equation, (c) the equilibrium constant from anti conformer to eclipsed conformer by using the equation including the change in Gibbs free energy. The dependence of tautomerism on solvent types was studied on the basis of UV-Vis spectra recorded in different organic solvents. The results showed that the compound exists in enol form in all solvents except ethyl alcohol.

Molecular structure, spectroscopic investigations, second-order nonlinear optical properties and intramolecular proton transfer of (E)-5-(diethylamino)-2-[(4-propylphenylimino)methyl]phenol: a combined experimental and theoretical study.

This work presents a combined experimental and theoretical study on an ortho-hydroxy Schiff base compound, (E)-5-(diethylamino)-2-[(4-propylphenylimino)methyl]phenol. The crystal structure and spectroscopic properties of the compound have been determined by using X-ray diffraction, IR and UV-vis spectroscopy techniques. The electronic structure, vibrational frequencies and electronic absorption spectra have been investigated from the calculative point of view. A relaxed potential energy surface scan has been performed based on the optimized geometry of OH tautomeric form to describe the potential energy barrier belonging to intramolecular proton transfer and to observe the effects of transfer on the molecular geometry. The second-order nonlinear optical properties have been investigated based on the first static hyperpolarizability (ß) by using the density functional theory.

Single stranded helical chains of C-H⋯π interactions further connected by halogen-halogen interactions of type I to construct supramolecular structure of (E)-5-(diethylamino)-2-[(4-iodophenylimino)methyl]phenol compound.

In this study, (E)-5-(diethylamino)-2-[(4-iodophenylimino)methyl]phenol compound was investigated from the point of stacking interactions assembling the supramolecular network, conformational isomerism and tautomerism. For this purpose, X-ray diffraction, FT-IR and UV/Vis spectroscopic techniques were used, giving the following structural and spectroscopic properties of the compound: The title compound has two conformers (anti and eclipsed) in the crystal structure resulting from rotation about C-N single bond of ethyl group. Both conformers prefer enol form in the solid state, adopting E configuration about the CN double bond. The supramolecular architecture of the compound is constructed by two non-covalent interactions as C-H⋯π and halogen-halogen interactions. The repetition of C-H⋯π interactions is resulted in a single-stranded helical structure. The helical structures are further connected by C-I⋯I-C interactions of Type I to construct the two dimensional supramolecular network defined as (6,3)-net in Wells nomenclature. The title compound adopts both enol and keto forms in EtOH (a polar and protic solvent) while enol form is preferred in the solid state.

Synthesis, spectroscopic characterizations and quantum chemical computational studies of (Z)-4-[(E)-p-tolyldiazenyl]-6-[(2-hydroxyphenylamino)methylene]-2-methoxycyclohexa-2,4-dienone.

In this study, the molecular structure and spectroscopic properties of title compound were characterized by X-ray diffraction, FT-IR and UV-vis spectroscopies. These properties of title compound were also investigated from calculative point of view. The X-ray diffraction and FT-IR analyses reveal the existence of keto form in the solid state. UV-vis spectra were recorded in different organic solvents. The results show that title compound exists in both keto and enol forms in DMSO, EtOH but it exists in enol form in benzene. In addition, the title compound in DMSO showed new absorption band at 436 nm due to the high ionizing effect of this solvent. The geometry optimization of title compound in gas phase was performed using DFT method with B3LYP applying 6-311G(d,p) basis set. TD-DFT calculations starting from optimized geometry were carried out in gas phase to calculate excitation energies of title compound. The non-linear optical properties were computed with the same level of theory and title compound showed a good second order nonlinear optical property. In addition, thermodynamic properties were obtained in the range of 100-500 K.

(E)-2-{[(2-(Trifluoro-meth-yl)phen-yl]imino-meth-yl}phenol.

In the crystal of the title compound, C(14)H(10)F(3)NO, intra-molecular O-H⋯N and O-H⋯F hydrogen bonds generate S(6) and S(10) intramolecular hydrogen-bonded rings. The dihedral angle between the planes of the aromatic rings is 13.00 (14)°.

2-Amino-3-(hy-droxy-meth-yl)pyridinium 2-benzoyl-benzoate monohydrate.

In the title hydrated salt, C(6)H(9)N(2)O(+)·C(14)H(9)O(3) (-)·H(2)O, the dihedral angle between the benzene rings of the 2-benzoyl-benzoate anion is 82.04 (14)°, while the angles between the aromatic ring of the pyridinium cation and each of the benzene rings of the anion are 4.42 (14) and 82.04 (14)°. In the crystal, mol-ecules are linked by N-H⋯O and O-H⋯O hydrogen bonds, generating a three-dimensional network with R(2) (2)(8), R(6) (6)(16) and R(4) (4)(6) motifs. The crystal packing is further stabilized by two π-π inter-actions, one between pyridinium rings, and another between the benzene benzoate and pyridinium rings of neighbouring mol-ecules, with centroid-to-centroid distances of 3.559 (2) and 3.606 (2) Å, respectively.

2-Amino-5-nitro-benzoic acid.

In the title compound, C(7)H(6)N(2)O(4), an intra-molecular N-H⋯O hydrogen bond generates an S(6) ring. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds generate R(2) (2)(8) loops. Inter-molecular N-H⋯O and C-H⋯O hydrogen bonds then link the dimers, generating R(3) (3)(16)R(2) (1)(6) motifs. The whole mol-ecule is essentially planar, with the greatest deviation from the mean plane being 0.065 (2) Å.

Synthesis, spectroscopic characterizations and quantum chemical computational studies of (Z)-4-[(E)-(4-fluorophenyl)diazenyl]-6-[(3-hydroxypropylamino)methylene]-2-methoxycyclohexa-2,4-dienone.

In this study, the molecular structure and spectroscopic properties of the title compound were characterized by X-ray diffraction, FT-IR and UV-vis spectroscopies. These properties were also investigated using DFT method. The most convenient conformation of title compound was firstly determined. The geometry optimizations in gas phase and solvent media were performed by DFT methods with B3LYP adding 6-31G(d) basis set. The differences between crystal and computational structures are due to crystal packing in which hydrogen bonds play an important role. UV-vis spectra were recorded in different organic solvents. The results show that title compound exists in both keto and enol forms in DMSO, EtOH but it tends to shift towards enol form in benzene. The polar solvents facilitate the proton transfer by decreasing the activation energy needed for Transition State. The formation of both keto and enol forms in DMSO and EtOH is due to decrease in the activation energy. TD-DFT calculations starting from optimized geometry were carried out in both gas and solution phases to calculate excitation energies of the title compound. The non-linear optical properties were computed at the theory level and the title compound showed a good second order non-linear optical property. In addition, thermodynamic properties were obtained in the range of 100-500K.

Probing the compound (E)-5-(diethylamino)-2-[(4-methylphenylimino)methyl]phenol mainly from the point of tautomerism in solvent media and the solid state by experimental and computational methods.

In this study, the molecular structure and spectroscopic properties of (E)-5-(diethylamino)-2-[(4-methylphenylimino)methyl]phenol were characterized experimentally by X-ray diffraction, FT-IR and UV-vis spectroscopic techniques and computationally by DFT method. It is concluded on the basis of X-ray diffraction and FT-IR analyses that the title compound exists in enol form in the solid state. UV-vis spectra of the title compound were recorded in different organic solvents to investigate the dependence of tautomerism on solvent types. The tautomerism-solvent relation was also studied by computational methods to have more insight on structural properties. The geometry optimization of the title compound in gas phase was performed by using DFT (B3LYP) method with 6-311G(d,p) basis set. The geometry optimizations in solvent media were carried out at the same theory level by the polarizable continuum model (PCM). In the calculation of excitation energies, TD-DFT calculations were carried out in both gas and solution phases. The computational investigation of non-linear optical properties indicates that the title compound has a good second order nonlinear optical property. The thermodynamic properties were obtained in the range of 100-500 K.

5-Diethyl-amino-2-[(E)-(4-eth-oxy-phen-yl)imino-meth-yl]phenol.

The title compound, C(19)H(24)N(2)O(2), adopts the phenol-imine tautomeric form. An intra-molecular O-H⋯N hydrogen bond results in the formation of a six-membered ring. The aromatic rings are oriented at a dihedral angle of 17.33 (16)°. Inter-molecular C-H⋯π inter-actions occur in the crystal.

(E)-5-Meth-oxy-2-(o-tolyl-imino-meth-yl)phenol.

In the title compound, C(15)H(15)NO(2), the phenol group make dihedral angles of 2.4 (2) and 24.1 (9)° with the imine linkage (-C=N-) and the phenyl group, respectively, and the mol-ecule adopts the enol-imine tautomeric form, so the mol-ecular structure is stabilized by a strong intra-molecular O-H⋯N hydrogen bond. The crystal structure features a weak C-H⋯π inter-action.

(E)-2-[(4-Fluoro-phen-yl)imino-meth-yl]-5-methoxy-phenol.

In the mol-ecule of the title compound, C(14)H(12)FNO(2), the aromatic rings are oriented at a dihedral angle of 48.17 (1)°. An intra-molecular O-H⋯N hydrogen bond results in the formation of a six-membered ring. The title mol-ecule is a phenol-imine tautomer, as evidenced by the C-O [1.351 (3) Å], C-N [1.282 (3) Å], and C-C [1.416 (3)-1.445 (3) Å] bond lengths. In the crystal, mol-ecules are linked by inter-molecular C-H⋯π inter-actions.

(E)-2-[(4-chlorophenyl)iminomethyl]-5-methoxyphenol and (E)-2-[(2-chlorophenyl)iminomethyl]-5-methoxyphenol: X-ray and DFT-calculated structures.

The crystal structures of the title 4-chlorophenyl, (I), and 2-chlorophenyl, (II), compounds, both C14H12ClNO2, have been determined using X-ray diffraction techniques and the molecular structures have also been optimized at the B3LYP/6-31 G(d,p) level using density functional theory (DFT). The X-ray study shows that the title compounds both have strong intramolecular O-H...N hydrogen bonds and that the crystal networks are primarily determined by weak C-H...pi and van der Waals interactions. The strong intramolecular O-H...N hydrogen bond is evidence of the preference for the phenol-imine tautomeric form in the solid state. The IR spectra of the compounds were recorded experimentally and also calculated for comparison. The results from both the experiment and theoretical calculations are compared in this study.

N-Cyano-7α-methoxy-carbonyl-6,14-endo-ethenotetra-hydro-northebaine.

IN THE TITLE COMPOUND (SYSTEMATIC NAME: methyl 17-cyano-3,6-dimeth-oxy-4,5α-ep-oxy-6,14-endo-ethenomorphinan-7-carboxyl-ate), C(23)H(24)N(2)O(5), the dihydro-furan ring adopts a twist conformation, while the piperidine ring is in a chair conformation. The benzene-fused cyclo-hexene ring adopts an envelope conformation. An intra-molecular C-H⋯O hydrogen bond is observed. Inter-molecular C-H⋯N and C-H⋯O hydrogen bonds form C(5) chains along the a and b axes, respectively, and together they form a three-dimensional network.

Dimethyl trans-3-(4-bromo-phen-yl)-2-methyl-isoxazolidine-4,5-dicarboxyl-ate.

In the title compound, C(14)H(16)BrNO(5), the isoxazolidine ring adopts an envelope conformation, with the N atom at the flap. In the crystal, inter-molecular C-H⋯N and C-H⋯O hydrogen bonds generate R(3) (3)(18) ring motifs which are fused into a ribbon-like structure extending along the b axis.